The effect of aging on the electromyographic activity of pelvic floor muscles. A comparative study among stress incontinent patients and asymptomatic women.

OBJECTIVES

Pelvic floor muscle training (PFMT) is commonly used in combination with biofeedback devices for stress urinary incontinence. A new electromyography (EMG)-based home-use device for PFMT is tested for healthy and stress incontinent patients.

SUBJECTS AND METHODS

Altogether 31 women with genuine stress incontinence (GSI) and 35 controls without urinary symptoms were measured with a vaginal surface EMG probe. EMG activity during three rapid contractions (5 s) in supine and standing positions were observed.

RESULTS

Mean values of three rapid contractions were 17.0 microV (range 6.5-59.0, S.D. 10.5) in the supine position and 12.9 microV (range 5.0-33.0, S.D. 5.9) in the standing position among incontinent patients and 19.5 microV (range 9.0-43.5, S.D. 8.4) and 18.2 microV (range 8.0-43.5, S.D. 8.7) among the controls, respectively. A significant difference (P=0.006) was found in the mean values of three rapid contractions in the standing position between GSI patients and asymptomatic women. In regression analysis, EMG values were dependent on age (P=0.004 in the supine, P=0.009 in the standing) in both groups, but not on parity, body mass index (BMI) or episiotomies.

CONCLUSIONS

In the study groups, the EMG activity of pelvic floor muscles (PFMs) decreased during aging. Although the tested surface EMG device showed a tendency that incontinent patients have lower PFM activities especially in the standing position, the value of surface EMG method as a diagnostic tool is not well established. However, the tested EMG-based device for PFMT will be helpful as guidance for incontinent patients.